1. Field of the Invention
The present invention relates to fuel additives and gasoline compositions effective for reducing intake valve deposits which do not contribute to increased deposit formation in port fuel injected engines.
2. Description of the Related Art
It is well known to those skilled in the art that internal combustion engines form deposits on the surface of engine components, such as carburetor ports, throttle bodies, fuel injectors, intake ports, and intake valves, due to the oxidation and polymerization of hydrocarbon fuel. Deposits also form in the combustion chamber of an internal combustion engine as a result of incomplete combustion of the mixture of air, fuel, and oil. These deposits, even when present in relatively minor amounts, often cause noticeable driving problems, such as stalling and poor acceleration. Moreover, engine deposits can significantly increase an automobile's fuel consumption and production of exhaust pollutants. Specifically, when the gasoline used in a given engine is of a constant octane number, the power output decreases when deposits are formed. In order to maintain the power output at a predetermined desired level, it then becomes necessary to increase the octane number of the fuel over the course of time. This Octane Requirement Increase (ORI) is undesirable. Therefore, the development of effective fuel detergents or deposit control additives to prevent or control such deposits is of considerable importance, and numerous such materials are known in the art.
Two general classes of additives are commercially known. One class comprises hydrocarbyl-substituted amines such as those prepared by reacting olefins and olefin polymers with amines (including polyamines). Typical examples of this class are polybutenyl amines. Another class of additives comprises the polyetheramines. Usually, these are "single molecule" additives, incorporating both amine and polyether functionalities within the same molecule. A typical example is an urethane product comprising repeating butylene oxide units under the trade name "Techron.TM." marketed by Chevron.
In some cases, the polyetheramines are preferred as the oxygenation (from the polyether functionality) is thought to lower particulate matter and nitrogen oxide (NOx) emissions and combustion chamber deposits. In addition, polyetheramines require little or no additional fluidizer oil to pass certain industry mandated valve stick requirements, resulting in a more economical final package. Polyisobutenyl amines, on the other hand, do require the addition of fluidizer oil to pass valve stick requirements and in addition are perceived to cause higher combustion chamber deposits than the fuel alone.
Canadian patent 1021157, Kreuz et al., Nov. 22, 1977 discloses a motor fuel composition comprising a mixture of hydrocarbons in the gasoline boiling range containing a minor amount of high molecular weight aliphatic hydrocarbon substituted or alkylated phenol in which the aliphatic hydrocarbon radical has an average molecular weight in the range from about 500-3500. This composition is useful in the prevention or inhibition of the formation of intake valve and port deposits in a gasoline engine, and also in enhancing the performance of the fuel composition in an engine designed to operate at significantly higher operating temperatures with a minimum of decomposition and deposit formation in the manifold of the engine.
U.S. Pat. No. 3,901,665, Polss, Aug. 26, 1975 discloses that combinations of (A) polymers of C.sub.3 -C.sub.4 olefins having a molecular weight in the range of about 400 to about 1400; and (B) polyoxyalkylene compounds of the formula ##STR2## wherein R is an alkyl group of 1 to 20 carbon atoms and wherein x has an average value of 4 to 20; are effective as anti-icing additives, as carburetor detergents, and in some instances as intake valve deposit modifiers.
U.S. Pat. No. 5,006,130, Aiello et al., Apr. 9, 1991, discloses a fuel additive for reducing intake valve deposits in electronic port fuel injected engines, said additive comprising a mixture of (a) about 2.5 parts per million per weight (ppmw) or higher of basic nitrogen based on the fuel composition in the form of an oil soluble aliphatic alkylene polyamine containing at least one olefinic polymer chain, said polyamine having a molecular weight of about 600 to about 10,000, and (b) from about 75 ppmw to about 125 ppmw based on the fuel composition of certain oil-soluble olefinic polymers, poly(oxyalkylene) alcohol, glycol or polyol or mono or di-ether thereof, non aromatic oils or polyalphaolefins.
U.S. Pat. No. 2,807,525, Foreman, Sep. 24, 1957, discloses a fuel composition characterized by a relatively low tendency to form gum deposits in the intake system and valves of an internal combustion engine and a relatively low freezing point containing an additive comprising an oil-soluble monobutoxy poly-1,2-oxypropylene glycol having a viscosity of from about 200 to 1000 SUS at 100.degree. F., and a water-miscible lower aliphatic hydrocarbon alcohol having from one to three carbon atoms in an amount within the range from 20% to 80% by volume to facilitate the solution of the polyoxyalkylene compound in the fuel and together with the polyoxyalkylene compound to reduce the freezing point of water present in the fuel.
U.S. Pat. No. 3,615,295, Manary, Oct. 26, 1971, discloses a fuel composition containing a small but effective amount of a polyalkoxylated alkylphenol of the general formula ##STR3## for reducing the hydrocarbon emission in the exhaust from an internal combustion engine.
U.S. Pat. No. 4,548,616, Sung et al., Oct. 22, 1985 discloses a fuel composition for reducing gasoline octane requirement, containing an additive, said additive comprising a poly(oxyethylene) poly(oxypropylene) poly(oxyethylene)polyol.
U.S. Pat. No. 4,877,416, Campbell, Oct. 31, 1989 discloses a synergistic fuel composition containing a hydrocarbyl-substituted amine or polyamine and a poly(oxyalkylene) monool, said composition providing for decrease in deposit formation correlated to Octane Requirement Increase (ORI).
U.S. Pat. No. 5,427,591, Cherpeck, Jun. 27, 1995 discloses a fuel additive of the formula: ##STR4## or a fuel-soluble salt thereof; wherein R.sub.1 and R.sub.2 are each independently hydrogen, hydroxy, lower alkyl having 1-6 carbon atoms, or lower alkoxy having 1-6 carbon atoms; R.sub.3 and R.sub.4 are each independently hydrogen or lower alkyl having 1 to 6 carbon atoms. These poly(oxyalkylene) hydroxyaromatic ethers were disclosed to be useful as fuel additives for the prevention and control of engine deposits.
U.S. Pat. No. 4,663,063, Davis, May 5, 1987, discloses a lubricant composition for use in two-cycle internal combustion engines containing an additive sufficient to control piston ring sticking and promote general engine cleanliness, said additive comprising:
(A) an alkylated phenol of the formula: ##STR5## wherein R' may be located ortho or para to the hydroxyl group and is a hydrocarbon-based group containing about 30 to about 400 aliphatic carbon atoms, R" is a lower alkyl and z is 0 or 1; and PA1 (B) a polyalkylene polyamine of the general formula ##STR6## or a derivative of such a polyalkylene polyamine wherein U is an alkylene group of from about 2 to about 10 carbon atoms, each R.sup.3 is independently selected from the group consisting of hydrogen and a hydrocarbon-based group containing 1-12 carbon atoms with the proviso that at least one R is a hydrogen atom, and n is a whole number of from 1 to about 10 wherein the weight ratio of (A):(B) is in the range of from abut 2:1 to about 400:1. PA1 (A) a polyether alcohol of the formula ##STR7## wherein in formula (A-1), R is hydrogen or a hydrocarbyl group of 1 to about 30 carbon atoms; R.sup.1 is hydrogen or a hydrocarbyl group of 1 to 5 carbon atoms or mixtures thereof; and x is a number from about 4 to about 40. PA1 (B) a hydrocarbylphenol having 1-3 hydrocarbyl groups such that the total weight average molecular weight of the hydrocarbyl groups is about 250 to about 6000. PA1 (1) hydrocarbon substituents, that is, aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, and aromatic-, aliphatic-, and alicyclic-substituted aromatic substituents, as well as cyclic substituents wherein the ring is completed through another portion of the molecule (e.g., two substituents together form an alicyclic radical); PA1 (2) substituted hydrocarbon substituents, that is, substituents containing non-hydrocarbon groups which, in the context of this invention, do not alter the predominantly hydrocarbon substituent (e.g., halo (especially chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso, and sulfoxy); PA1 (3) hetero substituents, that is, substituents which, while having a predominantly hydrocarbon character, in the context of this invention, contain other than carbon in a ring or chain otherwise composed of carbon atoms. Heteroatoms include sulfur, oxygen, nitrogen, and encompass substituents as pyridyl, furyl, thienyl and imidazolyl. In general, no more than two, preferably no more than one, non-hydrocarbon substituent will be present for every ten carbon atoms in the hydrocarbyl group; typically, there will be no non-hydrocarbon substituents in the hydrocarbyl group. PA1 (A) at least one olefinic compound containing at least one group of the formula ##STR12## and (B) at least one carboxylic reactant selected from the group consisting of compounds of the formula EQU R.sup.3 C(O)(R.sup.4).sub.n C(O)OR.sup.5 (IV) PA1 (C) ammonia or a hydrazine or an amine. PA1 R.sup.4 is a divalent hydrocarbylene group; PA1 n=0 or 1; PA1 y is an integer ranging from 1 to about 200; PA1 A is a hydrocarbyl group or a hydroxy-substituted hydrocarbyl group; and each of R.sup.9 and R.sup.10 is independently H, alkoxyhydrocarbyl, hydroxyhydrocarbyl, hydrocarbyl, aminohydrocarbyl, N-alkoxyalkyl- or hydroxyalkyl-substituted aminohydrocarbyl, or a group of the formula ##STR15## wherein each Y is a group of the formula EQU R.sup.11 --N(R.sup.12)--
The present invention provides a novel deposit control fuel additive composition comprising an alkylphenol, a polyether alcohol, and optionally a nitrogen-containing dispersant that is shown to give lower deposits in the intake valve and combustion chamber.